Testing and counterweight methods for dynamic balancing of wind turbine rotors

Abstract

This invention discloses a testing and counterweight method for the dynamic balancing of wind turbine rotors. First, the initial operating state O is tested, and the vibration amplitude and phase angle are recorded. Next, a counterweight belt Wg is attached to one blade, and its trial weight state O+T is tested, recording the vibration amplitude and phase angle. Finally, the counterweight vector T and the corrected counterweight Wb are calculated through vector calculation. The corrected counterweight is then distributed to two adjacent blades, and the calculated lead sand is added to the blade counterweight box, completing the counterweighting process. This method allows for a simple and rapid measurement of blade imbalance and accurate calculation of the required counterweight weight in the blade counterweight box, with a simple procedure.

Description

Technical fields:

[0001] This invention belongs to the field of dynamic balancing technology for wind turbine rotors, and specifically relates to a method for testing and counterweighting dynamic balancing of wind turbine rotors. Background technology:

[0002] As a key component for absorbing wind energy, the blades play a crucial role in the wind turbine. Imbalance in blade mass causes the main bearing load to fluctuate with the impeller speed, leading to serious damage to the main bearing over time, and potentially causing unnecessary safety hazards and economic losses. The quality of the blades varies significantly depending on the number of glass cloth layers, the amount of adhesive applied, and the surface paint. Currently, blades are weighed in the manufacturing plant, and three blades of similar weight are installed on the same unit. However, differences in shape and uneven material distribution among the three blades can cause overall impeller mass imbalance.

[0003] Currently, there are limited methods for measuring impeller mass imbalance. The most common method is to measure the vibration of the main bearing to see if there is a 1X frequency impact. Then, based on experience, an appropriate amount of lead sand is added to the corresponding blade counterweight box, and the test is repeated until the impact energy is reduced to a reasonable range.

[0004] However, the above method can only roughly estimate the size of the counterweight based on experience, and it requires multiple retests and repeated counterweighting to reduce the imbalance to an acceptable range, which is time-consuming and cumbersome.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention:

[0006] The purpose of this invention is to provide a method for testing and counterweighting the dynamic balance of a wind turbine rotor, thereby overcoming the defects in the prior art.

[0007] To achieve the above objectives, the present invention provides a method for testing and counterweighting the dynamic balancing of wind turbine rotors, comprising the following steps:

[0008] S1: Draw a polar coordinate diagram in the stopped state, mark the phase angle of 0 degrees in the +Y direction of the locking plate, and divide the entire circle into 360 degrees, indicating the rotation direction and phase angle;

[0009] S2: Install a vibration sensor in the vertical direction of the main bearing to measure its vibration value;

[0010] S3: Start the machine. Once the unit is running stably, record the impeller speed n and measure its initial vibration state O.

[0011] S4: Stop the machine and brake, then lock the hub. Tie a counterweight belt to the blades adjacent to the initial state O in S3. The mass of the counterweight belt is Wg, and record the phase angle θ4 = 120 degrees and the distance from the impeller center as L.

[0012] S5: Restart the machine and wait for the unit to run stably until the impeller speed is n. Measure its vibration state O+T after counterweight.

[0013] S6: Draw the state of T in the figure, set the vibration value as A3, and move T to the center point. Calculate the phase angle θ3 between T and O in the opposite direction.

[0014] S7: Calculate the corrected counterweight Wb and the corresponding phase angle θ5;

[0015] S8: Distribute the corrected counterweights into the counterweight boxes of adjacent blades;

[0016] S9: Add the calculated amount of lead sand to the counterweight boxes of adjacent blades, and seal the counterweight boxes to complete the counterweighting.

[0017] Furthermore, as a preferred embodiment, the wind turbine generator set in S1 has three evenly distributed blades, namely blade 1, blade 2, and blade 3. Blade 2 and blade 3 are respectively equipped with counterweight boxes. Blade 1 is vertically upward, so the phase angle of blade 1 is 0 degrees.

[0018] Furthermore, preferably, the vibration state measured in S3 and S5 includes the vibration value An and the phase angle θn.

[0019] Furthermore, as a preferred option, the unit operates at a consistent speed in S3 and S5.

[0020] Furthermore, as a preferred embodiment, before distributing the counterweights in S8, the distances L2 and L3 between the counterweight boxes of blades 2 and 3 and the center of the generator blades are measured.

[0021] Compared with the prior art, one aspect of the present invention has the following beneficial effects:

[0022] (1) The operation steps of this invention are simple. The amount of blade imbalance can be obtained by initial operation and trial operation, which reduces the number of repeated balancing and can reduce labor costs.

[0023] (2) By using the method of the present invention, the blade imbalance can be obtained through vector calculation, so that the imbalance can be allocated to the specific blade counterweight box to achieve precise counterweight, reduce the blade imbalance, reduce the vibration value of the unit, and avoid safety hazards and economic losses caused by blade imbalance of the wind turbine generator set. Attached image description:

[0024] Figure 1This is a schematic diagram of the polar coordinates of S1 in this invention;

[0025] Figure 2 This is a schematic diagram of the initial vibration state of S3 in this invention;

[0026] Figure 3 This is a schematic diagram of the counterweight in S4 of the present invention;

[0027] Figure 4 This is a schematic diagram of the S5 trial run in this invention;

[0028] Figure 5 This is a schematic diagram of the S6 counterweight vector calculation in this invention;

[0029] Figure 6 This is a schematic diagram of the S7 corrected counterweight in this invention;

[0030] Figure 7 This is a schematic diagram of the S8 counterweight distribution in this invention. Detailed implementation method:

[0031] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0032] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0033] A method for testing and counterweighting the dynamic balance of wind turbine rotors, characterized by comprising the following steps:

[0034] S1: Stop the machine with blade 1 pointing vertically upwards. Draw a polar coordinate diagram in the stopped state, marking the phase angle as 0 degrees in the +Y direction of the locking disc. Divide the entire circle into 360 degrees, indicating the rotation direction and phase angle, as follows: Figure 1 As shown;

[0035] S2: A vibration sensor is installed in the vertical direction of the main bearing to measure its vibration value;

[0036] S3: Start-up. Once the unit is running stably, record the impeller speed n and measure its initial vibration state O. The vibration value is A1 and the initial phase angle is θ1. Figure 2 As shown;

[0037] S4: Stop the machine and apply the brakes, then lock the hub. Tie a counterweight belt to the blade adjacent to the impeller in the opposite direction of the initial state O in S3 (e.g., blade 3). The mass of the counterweight belt is Wg, and record the phase angle θ4 = 120 degrees and the distance from the impeller center as L. Figure 3 As shown;

[0038] S5: Start the unit and wait until the impeller speed reaches n when it is running stably. Measure the vibration state O+T after counterweighting, with vibration value A2 and phase angle θ2. Figure 4 As shown;

[0039] S6: Plot the state of T in the diagram, set the vibration value to A3, and move T to the center point. Calculate the phase angle θ3 between T and O in opposite directions. Figure 5 As shown, the specific calculations are as follows:

[0040] According to the formula: A1 sinθ3=A2 sin(180-(θ2-θ1)-θ3)

[0041] The calculation shows that:

[0042] A3=A1cosθ3+A2cos(180-θ2+θ1);

[0043] S7: Calculate the corrected counterweight Wb and the corresponding phase angle θ5, as follows: Figure 6 As shown, the details are as follows:

[0044] Wb = Wg × A1 / A3

[0045] θ5 = θ4 + θ3 = 120 + θ3;

[0046] S8: Distribute the corrected counterweights into the counterweight boxes of adjacent blades, such as... Figure 7 As shown, the details are as follows:

[0047] The distance from the counterweight box of blade 3 to the center of the impeller is L3, requiring an additional counterweight M3. The distance from the counterweight box of blade 2 to the center of the impeller is L2, requiring an additional counterweight M2. The calculations based on vectors are as follows:

[0048] M3×L3=Wg×L×(cosθ3+sinθ3ctg60) 2

[0049] M3=Wg×L×(cosθ3+sinθ3ctg60) 2 / L3

[0050] M2×L2=Wg×L×sinθ3 / sin60

[0051] M2=Wg×L×sinθ3 / sin60 / L2;

[0052] S9: Add lead sand of mass M2 and mass M3 to the counterweight boxes of blade 2 and blade 3 respectively, and seal the counterweight boxes to complete the counterweighting.

[0053] This method can easily and quickly measure the imbalance of the blade and accurately calculate the amount of counterweight to be added to the blade counterweight box. The process is simple.

[0054] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for testing and counterweighting the dynamic balance of wind turbine rotors, characterized in that, Includes the following steps: S1: Draw a polar coordinate diagram in the stopped state, mark the phase angle of 0 degrees in the +Y direction of the locking plate, and divide the entire circle into 360 degrees, indicating the rotation direction and phase angle; S2: Install a vibration sensor in the vertical direction of the main bearing to measure its vibration value; S3: Start-up. Once the unit is running stably, record the impeller speed n and measure its initial vibration state O. The vibration value is A1 and the initial phase angle is θ1. S4: Stop the machine and brake, then lock the impeller. Tie a counterweight belt to the blades adjacent to the initial state O in S3. The mass of the counterweight belt is Wg, and record the phase angle θ4 = 120 degrees and the distance from the impeller center as L. S5: Restart the unit and wait until the impeller speed is n when the unit is running stably. Measure the vibration state O+T after the counterweight. The vibration value is A2 and the phase angle is θ2. S6: Plot the state of T in the diagram, set the vibration value as A3, and move T to the center point. Calculate the phase angle θ3 between T and O in opposite directions. θ3 is obtained according to the following formula: θ3=arctan[ In the formula, A1 is the vibration value in the initial state, θ1 is the phase angle in that state, A2 is the vibration value in the O+T state, and θ2 is the phase angle in that state; where A1 sinθ3=A2 sin(180-(θ2-θ1)-θ3) and A3=A1cosθ3+A2cos(180-θ2+θ1); S7: Calculate the corrected counterweight Wb and the corresponding phase angle θ5, where θ5 = 120 + θ3; S8: Distribute the corrected counterweights into the counterweight boxes of adjacent blades; S9: Add the calculated amount of lead sand to the counterweight boxes of adjacent blades, and seal the counterweight boxes to complete the counterweighting.

2. The method for testing and counterweighting the dynamic balance of wind turbine rotors according to claim 1, characterized in that, The wind turbine generator set in S1 has three evenly distributed blades, namely blade 1, blade 2 and blade 3. Blade 2 and blade 3 are respectively equipped with counterweight boxes. Blade 1 is vertically upward, so the phase angle of blade 1 is 0 degrees.

3. The method for testing and counterweighting the dynamic balance of wind turbine rotors according to claim 1, characterized in that, The vibration state measured in S3 and S5 includes the vibration value An and the phase angle θn.

4. The method for testing and counterweighting the dynamic balance of wind turbine rotors according to claim 1, characterized in that, The unit operates at a consistent speed in S3 and S5.

5. The method for testing and counterweighting the dynamic balance of wind turbine rotors according to claim 2, characterized in that, In S8, before distributing the counterweights, the distances L2 and L3 between the counterweight boxes of blades 2 and 3 and the center of the generator blades are measured.

Images